1. Field of the Invention
This invention relates to a valve train device for an engine and, more particularly, to a valve train device which can continuously change valve opening duration and/or the amount of valve lift.
2. Description of the Related Art
It is known in the art how to provide engines with valve train devices that are capable of continuously changing intake valve opening duration and/or the amount of valve lift. An example of such a valve train device comprises a camshaft, which drives an intake valve to open and close through a rocker arm. This device is arranged in such a way that a swing member is pivoted by the camshaft. A control arm is interposed between a swing cam surface of the swing member and a rocker-side depressed surface of the rocker arm. The valve opening duration and the amount of valve lift is continuously varied by changing a position of the control arm that comes into contact with the swing cam surface and a position of the control arm that comes into contact with the rocker-side depressed surface (See e.g., JP-A-Sho 59-500002).